Hydrogen, which is an energy source of the future and also a fundamental material in chemical and electronic industry processes, is being manufactured through a variety of paths.
Of various reactions, a steam reforming reaction (Reaction Formula 1, hereinafter referred to as an “SR”) using a natural gas is widely used industrially because of its high concentration of resulting hydrogen.CH4+H2OCO+3H2, reaction heat=205.8 kJ/mol  Reaction Formula 1
After reaction of Reaction Formula 1, a carbon monoxide transfer reaction (water gas shift, hereinafter referred to as a “WGS”) is conducted to increase a hydrogen concentration according to Reaction Formula 2, and subsequently the process of separating hydrogen is carried out in the cooling/water removal, pressure swing adsorption (PSA) unit processes.CO+H2OCO2+H2, reaction heat=−41.2 kJ/mol  Reaction Formula 2
The SR reaction relevant to Reaction Formula 1 is an equilibrium reaction with a large amount of heat absorption, wherein a high temperature is inevitable. The WGS reaction according to Reaction Formula 2 is an equilibrium reaction and the process temperature is increased by the generated heat. Because of that, it is inevitable that the reaction gas is required to be cooled after a high temperature shift (HTS) reaction followed by a low temperature shift (LTS) reaction. Therefore, the whole process is carried out in a huge plant, and there is a problem of low heat efficiency. Thus, it is necessary to develop a new process to substitute this.
In order to improve the above-described problems, research into a metal catalyst with a fast heat transfer rate and a micro-channel reactor using the same is under way.
In addition, based on the idea that a hydrogen generation reaction is an equilibrium reaction, Mitsubishi Heavy Industries of Japan has worked on the development of a simplified process in which a hydrogen separation membrane is used to break equilibrium by removing hydrogen simultaneously with the reaction, and thereby high-concentration hydrogen can be obtained simultaneously with a low-temperature reforming reaction. (Y. Shirasaki et al, Development of membrane reformer system for highly efficient hydrogen production from natural gas, Int. J. Hydrogen Energy, 34 (2009) 4482-4487, K.-R. Hwang et al., A catalytic membrane reactor for water-gas shift reaction, Korean J. Chem. Eng., 27 (3) (2010) 816-821).
As above-described method, Hwang et al. improved the transfer rate of carbon monoxide by removing hydrogen simultaneously with the carbon monoxide aqueous reaction.
The essential point in the two reactors described above is in disposing catalyst around the separation membrane as a configuration method of catalyst and reactor, and many researchers have put in a great deal of effort for this. In such a configuration, a metal web coated with catalyst is located at a near distance but not in contact with the separation membrane, or a fine powder catalyst is located in a basket to maintain a certain interval with the separation membrane. That is, the positions of the separation membrane and the catalyst are fixed, and only the catalyst is located at the entrance of the reactor because the amount of generated hydrogen is small especially at the entrance thereof, and from the latter half of a certain distance, the separation membrane is located around the catalyst. Such a configuration is at no more than a research stage for verifying a possibility of a simultaneous process of reaction separation, and consequently there are many problems as a technology for efficiency maximization or for scaling up to a large volume. Especially in order to maximize the reaction separation effect, a configuration that can raise the reaction operation pressure is necessary. For this, a new approach is necessary due to structural characteristics.
That is, there is a big difference in performance according the spatial configuration method between the separation membrane and the catalyst. By considering making it for a large volume and mass production, it can be seen that a configuration that is easy to scale up is necessary.